The ATP confirmed on Thursday: "The ATP has announced that Nick Kyrgios has been fined for an insulting remark made to Stanislas Wawrinka during his second round match against Wawrinka at the Rogers Cup in Canada."

Details of the fine are not being made public until after Kyrgios has been notified.

Kyrgios won Wednesday's contest after the Swiss retired hurt, but it was an apparent exchange at the end of the first set which become the focal point.

On-court microphones recorded 20-year-old Kyrgios walking to the net and saying: "Kokkinakis banged your girlfriend. Sorry to tell you that mate" - an apparent reference to Australian Davis Cup team-mate Thanasi Kokkinakis.

Speaking on court afterwards, Kyrgios claimed he had been provoked, saying: "He was getting a bit lippy with me. Kind of in the heat of the moment, I don't know. I just said it."

Later in the same match Kyrgios was again caught on microphones around the court muttering the words "banging an 18-year-old":

Writing on Twitter, Wawrinka said: "So disappointing to see a fellow athlete and colleague be so disrespectful in a way I could never even imagine.

"What was said I wouldn't say to my worst enemy. To stoop so low is not only unacceptable but also beyond belief.

"There is no need for this kind of behaviour on or off the court and I hope the governing body of this sport does not stand for this and stands up for the integrity of this sport that we have worked so hard to build."

Controversy has followed Kyrgios around since his 2014 breakthrough when he knocked Rafael Nadal out of Wimbledon.